AP1510. General Description. Features. Applications. Typical Application Circuit PWM CONTROL 3A STEP-DOWN CONVERTER AP1510. x (1+R A = V FB /R B

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1 Features General Description Input voltage: 3.6 to 23 Output voltage: 0.8 to CC. Duty ratio: 0% to 100% PWM control Oscillation frequency: 300kHz typ. Current Limit, Enable function Thermal Shutdown function Builtin internal SW Pchannel MOS SOP8L PbFree Package SOP8L: Available in Green Molding Compound (No Br, Sb) Lead Free Finish/ RoHS Compliant (Note 1) AP1510 consists of stepdown switching regulator with PWM control. These devices include a reference voltage source, oscillation circuit, error amplifier and internal PMOS. AP1510 provides lowripple power, high efficiency and excellent transient characteristics. The PWM control circuit is able to vary the duty ratio linearly from 0 up to 100%. This converter also contains an error amplifier circuit. An enable function, an over current protection and a short circuit protection are built inside, when OCP or SCP happens, the operation frequency will be reduced from 300kHz to 30kHz. Also, an internal compensation block is built in to minimum external component count. With the addition of an internal Pchannel Power MOS, a coil, capacitors, and a diode connected externally, these ICs can function as stepdown switching regulators. They serve as ideal power supply units for portable devices when coupled with the SOP8L package, providing such outstanding features as low current consumption. Since this converter can accommodate an input voltage up to 23, it is also suitable for the operation via an AC adapter. Applications Cellular Phones PC Motherboard LCD Monitor Graphic Card DDideo Player Telecom Equipment ADSL Modem Printer and other Peripheral Equipment Microprocessor core supply Networking power supply Typical Application Circuit IN cc Output L1 22uH OUT =5/3A C IN 470uF Ccc 0.1uF R 3.9K C Option R 100K C 0.1uF AP1510 SS D1 C C Optional R A 6.8K R B 1.3K C 0.1uF C OUT 470uF Note: OUT = x (1R A /R B ) R B =0.7K~5K ohm AP1510 Rev. 7 1 of 9 JULY 2009

2 Ordering Information AP1510 S X 13 Package S : SOP8L Lead Free L : Lead Free G : Green Packing 13 : Tape & Reel Leadfree Device Package Packaging 13 Tape and Reel Code (Note 2) Quantity Part Number Suffix AP1510SL13 S SOP8L 2500/Tape & Reel 13 AP1510SG13 S SOP8L 2500/Tape & Reel 13 Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at 2. Pad layout as shown on Diodes Inc. suggested pad layout document AP02001, which can be found on our website at Pin Assignments ( Top iew ) 1 8 ss 2 3 AP ss Output CC 4 5 Output SOP8L Pin Descriptions Pin Name Pin NO. Description 1 Feedback pin. 2 Enable Input pin H: Normal operation (Stepdown operation) L: Stepdown operation stopped (All circuits deactivated) 3 Add an external resistor to set max output current. CC 4 IC power supply pin Output 5, 6 Switch Pin. Connect external inductor/diode here. Minimize trace area at this pin to reduce EMI. SS 7, 8 GND Pin AP1510 Rev. 7 2 of 9 JULY 2009

3 Block Diagram Output cc Oscillation Circuit Reference oltage Source with Soft Start Thermal Shutdown PWMSwitched Control Circuit 100uA ss Absolute Maximum Ratings Symbol Parameter Rating Unit CC CC Pin oltage SS 0.3 to SS 25 Feedback Pin oltage SS 0.3 to CC Pin oltage SS 0.3 to IN 0.3 OUT Switch Pin oltage SS 0.3 to IN 0.3 P D Power Dissipation Internally limited mw T OP Operating Junction Temperature Range 20 to 125 o C T ST Storage Temperature Range 65 to 150 o C Caution: The absolute maximum ratings are rated values exceeding which the product could suffer physical damage. These values must therefore not be exceeded under any conditions. Recommended Operating Conditions Symbol Parameter Min Max Unit IN Input oltage I OUT Output Current 0 3 A T A Operating Ambient Temperature o C AP1510 Rev. 7 3 of 9 JULY 2009

4 Electrical Characteristics (IN = 12, T a = 25 C, unless otherwise specified) Symbol Parameter Conditions Min Typ. Ma. Unit Feedback oltage I OUT = 0.1A I Feedback Bias Current I OUT = 0.1A µa I SW Switch Current 3.5 A Current Consumption During Power Off = 0 10 µa I SHDN OUT / IN OUT / OUT Line Regulation IN = 5~23, I OUT = 0.2A 1 2 % Load Regulation I OUT = 0.1 to 3A % f OSC Oscillation Frequency Measure waveform at SW pin khz f OSC1 Frequency of Current Limit or Short Circuit Protect Measure waveform at SW pin 10 khz IH Evaluate oscillation at SW pin 2.0 Pin Input oltage IL Evaluate oscillation stop at SW pin 0.8 I H 20 µa Pin Input Leakage Current I L 10 µa I Pin Bias Current µa T SS SoftStart Time ms T SHDN Thermal shutdown threshold 150 C T HYS Thermal shutdown hysteresis 55 C R DSON Internal MOSFET Rdson EFFI θ JA θ JC Notes: Efficiency Thermal Resistance JunctiontoAmbient Thermal Resistance JunctiontoCase IN = 5, = IN =12, = IN = 12, OUT = 5 I OUT = 3A mω 91 % SOP8L (Note 3) 134 SOP8L (Note 3) Test condition: Device mounted on FR4 substrate 2oz copper, minimum recommended pad layout, single side. For better thermal performance, please arrange larger copper pad of layout for heatsink. o C/W o C/W AP1510 Rev. 7 4 of 9 JULY 2009

5 Typical Performance Characteristics Fosc (khz) AP1510 in vs. Frequency (out=3.3; Iout=0.2A) in () () AP1510 in vs. (out=3.3; Iout=0.2A) in () out() AP1510 Line Regulation (out=3.3; Iout=0.2A) in() out (A) AP1510 Load Regulation (in=12) Iout (A) Efficiency (%) AP1510 Efficiency out: out: Iout (A) AP1510 Rev. 7 5 of 9 JULY 2009

6 Typical Performance Characteristics (Continued) AP1510 out Ripple (in=12; out=3.3; Iout=0.1A) AP1510 out Ripple (in=12; out=3.3; Iout=3A) Test Circuit A open CC OUTPUT SS open Oscillation A OUTPUT CC SS Enable function test Feedback function test OUTPUT CC SS Operation function test AP1510 Rev. 7 6 of 9 JULY 2009

7 Functional Description PWM Control The AP1510 is a DC/DC converter that employs pulse width modulation (PWM) scheme. Its pulse width varies in the range of 0% to 99%, based on the output current loading. The output ripple voltage caused by the PWM high frequency switching can easily be reduced through an output filter. Therefore, this converter provides a low ripple output supply over a broad range of input voltage & output current loading Under oltage Lockout The under voltage lockout circuit of the AP1510 assures that the highside MOSFET driver remains in the off state whenever the supply voltage drops below 3.3. Normal operation resumes once CC rises above 3.5. Current Limit Protection The current limit threshold is set by external resistor R connected from CC supply to pin. The internal sink current I (90μA typical) across this resistor sets the voltage at pin. When the PWM voltage is less than the voltage at, an overcurrent condition is triggered. The current limit threshold is given by the following equation: where, I PEAK R I PEAK DS(ON) > I = I OUT(MAX) R (ΔI) 2 IN OUT Δ I = OUT fs L IN I PEAK is the output peak current; R DS (ON) is the MOSFET ON resistance; f S is the PWM frequency (300KHz typical). Also, the inductor value will affect the ripple current ΔI. The above equation is recommended for input voltage range of 5 to 18. For input voltage lower than 5 or ambient temperature over 100 C, higher R is recommended. Inductor Selection For most designs, the operation range with inductors is from 22µH to 33µH. The inductor value can be derived from the following equation: IN OUT L = OUT fs ΔI IN Where ΔI L is inductor Ripple Current. Large value inductors lower ripple current and small value inductors result in high ripple current. Choose inductor ripple current approximately 15% of the maximum load current 3A, I L=0.45A. The DC current rating of the inductor should be at least equal to the maximum load current plus half the ripple current to prevent core saturation (3A0.225A). Input Capacitor Selection This capacitor should be located close to the IC using short leads and the voltage rating should be approximately 1.5 times the maximum input voltage. The RMS current rating requirement for the input capacitor of a buck regulator is approximately 1 2 the DC load current. A low ESR input capacitor sized for maximum RMS current must be used. A 470µF low ESR capacitor for most applications is sufficient. Output Capacitor Selection The output capacitor is required to filter the output voltage and provides regulator loop stability. The important capacitor parameters are the 100KHz Equivalent Series Resistance (ESR), the RMS ripples current rating, voltage rating and capacitance value. For the output capacitor, the ESR value is the most important parameter. The output ripple can be calculated from the following formula. RIPPLE = ΔI L ESR The bulk capacitor s ESR will determine the output ripple voltage and the initial voltage drop after a high slewrate transient. An aluminum electrolytic capacitor's ESR value is related to the capacitance and its voltage rating. In most case, higher voltage electrolytic capacitors have lower ESR values. Most of the time, capacitors with much higher voltage ratings may be needed to provide the low ESR values required for low output ripple voltage. PCB Layout Guide If you need low T C & T J or large P D (Power Dissipation), The dual SW pins(5& 6) and ss pins(7& 8)on the SOP8L package are internally connected to die pad, The evaluation board should be allowed for maximum copper area at output (SW) pins. 1. Connect circuits as closely as possible and keep away from inductor flux for pure. 2. Connect input capacitor to cc and ss pin as closely as possible to get good power filter effect. 3. Connect R to cc and pin as closely as possible. 4. Connect ground side of the input capacitor & Schottky & output capacitor as closely as possible and use ground plane for best performance. AP1510 Rev. 7 7 of 9 JULY 2009

8 Marking Information (1) SOP8L Logo Part Number ( Top iew ) 8 5 AP1510 YY WW X X 1 4 L : Lead Free G : Green YY : Year : 08, 09,10~ WW : Week : 01~52; 52 represents 52 and 53 week X : Internal Code Package Information (All Dimensions in mm) (1) Package type: SOP8L 3.85/ / / Gauge Plane Seating Plane 0.62/0.82 Detail "A" 7 ~9 0.35max ~9 1.30/ max. 0.15/0.25 Detail "A" 0 /8 1.27typ 0.3/ /4.95 8x x1.27 8x1.55 Land Pattern Recommendation (Unit: mm) AP1510 Rev. 7 8 of 9 JULY 2009

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